The Trump administration this week continued its assault on the California environment, this time undermining decade-old protections for the Sacramento-San Joaquin River Delta.

New politically driven environmental findings announced Tuesday are designed to enable the shipping of more water to Southern California farmers, endangering the health of the Delta and threatening native fish that are on the brink of extinction.

The question now is whether Gavin Newsom will respond by standing up for protection of California’s waterways with the vigor that he opposes Trump’s attack on the state’s auto emissions standards. Or will the governor capitulate to the same lobbying pressure from farmers and water agencies that are pushing the president’s Delta policies?

It’s time for Newsom to demonstrate that he’s serious about protecting all aspects of the state’s environment.

The Delta is the largest estuary west of the Mississippi, supplying fresh water for 25 million Californians, including about one-third of Bay Area residents. But decades of overpumping to Southern California and the Central Valley threatens the Delta’s ability to provide fresh water for current and future generations. Climate change exacerbates the danger.

Ironically, the review of current pumping began during the Obama administration because of concern that fishery protections were not strong enough. Now the Trump administration has flipped the review on its head, using the effort to weaken those protections.

The push is being driven by politics rather than good policy, starting with Trump’s insistence on clearing the way for delivery of more water to farmers and his disdain for Delta environmental protections.

The point person is Interior Secretary David Bernhardt, who was a lobbyist and lawyer for the 600,000-acre Central Valley Westlands Water District, which serves farmers who have been fighting for decades for more water from the Delta. Bernhardt personally argued an appeals case challenging salmon protections.

The Trump administration’s new “biological opinions,” released Tuesday, come from two agencies under Bernhardt’s control, U.S. Fish and Wildlife Service and National Marine Fisheries Service.

The opinions claim that pumping more water south will not harm the estuary’s Delta smelt, which are on the brink of extinction, and three types of salmon, which are endangered or threatened.

But that’s not what experts in those agencies said last summer. In a July 1 assessment, federal scientists found that increasing water exports would harm endangered fish. That report was never released, and the team of scientists were replaced, according to the Los Angeles Times, which obtained the document.

The latest findings, of no potential harm to the fish from increased water exports, was produced by the replacement team.

The state Legislature, anticipating this moment, passed a bill this year that would have locked in for California federal environmental protections that were in place when Trump took office. But Newsom vetoed Senate Bill 1, saying the bill was unnecessary but assuring he would continue fighting against the Trump administration to protect the environment.